Abstracts of Selected Recent NBER Working Papers

WP 16164
Martin Gaynor, Rodrigo Moreno-Serra, Carol Propper
Death by Market Power: Reform, Competition and Patient Outcomes in the National Health Service

The effect of competition on the quality of health care remains a contested issue. Most empirical estimates rely on inference from non experimental data. In contrast, this paper exploits a pro-competitive policy reform to provide estimates of the impact of competition on hospital outcomes. The English government introduced a policy in 2006 to promote competition between hospitals. Patients were given choice of location for hospital care and provided information on the quality and timeliness of care. Prices, previously negotiated between buyer and seller, were set centrally under a DRG type system. Using this policy to implement a difference-in-differences research design we estimate the impact of the introduction of competition on not only clinical outcomes but also productivity and expenditure. Our data set is large, containing information on approximately 68,000 discharges per year per hospital from 162 hospitals. We find that the effect of competition is to save lives without raising costs. Patients discharged from hospitals located in markets where competition was more feasible were less likely to die, had shorter length of stay and were treated at the same cost.

WP 16171
Marcella Alsan, David Cutler
The ABCDs of Health: Explaining the Reduction in AIDS in Uganda

Uganda was widely viewed as a public health success for curtailing its AIDS epidemic in the early 1990s. To understand the reasons for the dramatic decline, we build a simulation model of HIV transmission using newly discovered data on HIV status and sexual behavior from the relevant time period. We then model the impact of abstinence, fidelity, condom use and selective mortality on the prevalence of HIV among various subgroups. Among young women, who experienced the greatest decline in HIV prevalence, the most important component was delaying sexual debut, accounting for 57 percent of the drop in HIV prevalence. Condom use by high risk males and to a lesser extent death (of older males) also played a significant role, accounting for 30 and 16 percent respectively. However, for older women, the trend is reversed, with death being more important than abstinence or condom usage. All told, we explain 86 percent of the reduction in AIDS in Uganda.

WP 16179
Carrie Hoverman Colla, William Dow, Arinkrajit Dube
How Do Employers React to a Pay-or-Play Mandate? Early Evidence from San Francisco

In 2006 San Francisco adopted major health reform, becoming the first city to implement a pay-or-play employer health spending mandate. It also created Healthy San Francisco, a "public option" to promote affordable universal access to care. Using the 2008 Bay Area Employer Health Benefits Survey, we find that most employers (75%) had to increase health spending to comply with the law, yet most (64%) are supportive of the law. There is substantial employer demand for the public option, with 21% of firms using Healthy San Francisco for at least some employees, yet there is little evidence of firms dropping existing insurance offerings in the first year after implementation.

Public financing of private health insurance may generate external effects beyond the subsidized population, by influencing the size and bargaining power of health insurers. We test for this external effect in the context of Medicare Part D. We analyze how Part D-related insurer size increases impacted retail drug prices negotiated by insurers for their non-Part D commercial market. On average, Part D lowered retail prices for commercial insureds by 5.8% to 8.5%. The cost-savings to the commercial market amount to $3bn per year, which approximates the total annual savings experienced by Part D beneficiaries who previously lacked drug coverage.

WP 16252
John Komlos, Marek Brabec
The Trend of BMI Values of US Adults by Centiles, birth cohorts 1882-1986

Trends in BMI values are estimated by centiles of the US adult population by birth cohorts 1882-1986 stratified by ethnicity. The highest centile increased by some 18 to 22 units in the course of the century while the lowest ones increased by merely 1 to 3 units. Hence, the BMI distribution became increasingly right skewed as the distance between the centiles became increasingly larger. The rate of change of BMI centile curves varied considerably over time. The BMI of white men and women experienced upsurges after the two World Wars and downswings during the Great Depression and again after 1970. However, among blacks the pattern is different during the first half of the century with men's rate of increase in BMI values decreasing substantially and that of females remaining unchanged at a relatively high level until the Second World War. However, after the war the rate of change of BMI values of blacks resembled that of the whites with an accelerating phase followed by a slow down around the 1970s. In sum, the creeping nature of the obesity epidemic is evident, as the technological and lifestyle changes of the 20th century affected various segments of the population quite differently.

This paper explores price differences in the European Union (EU) pharmaceutical market, the EU's fifth largest industry. With the aim of enhancing quality of life along with industry competitiveness and R&D capability, many EU directives have been adopted to achieve a single EU-wide pharmaceutical market. Using annual 1994-2003 data on prices of molecules that treat cardiovascular disease, we examine whether drug price dispersion has indeed decreased across five EU countries. Hedonic regressions show that over time, cross-country price differences between Germany and three of the four other EU sample countries, France, Italy and Spain, have declined, with relative prices in all three as well as the fourth country, UK, rising during the period. We interpret this as evidence that the EU has come closer to achieving a single pharmaceutical market in response to increasing European Commission coordination efforts.

Economists have puzzled over why eligible individuals fail to enroll in social safety net programs. "Chilling effects" arising from an icy policy climate are a popular explanation for low program take-up rates among immigrants, but such effects are inherently hard to measure. This paper investigates a concrete determinant of chilling, Federal immigration enforcement, and finds robust evidence that heightened enforcement reduces Medicaid participation among children of non-citizens. This is the case even when children are themselves citizens and face no eligibility barriers to Medicaid enrollment. Immigrants from countries with more undocumented U.S. residents, those living in cities with a high fraction of other immigrants, and those with healthy children are most sensitive to enforcement efforts. Up to seventy-five percent of the relative decline in non-citizen Medicaid participation around the time of welfare reform, which has been attributed to the chilling effects of the reform itself, is explained by a contemporaneous spike in immigration enforcement activity. The results imply that safety net participation is influenced not only by program design, but also by a broader set of seemingly unrelated policy choices.

This paper examines the correlation between poor health and asset accumulation for households in the first nine waves of the Health and Retirement Survey. Rather than enumerating the specific costs of poor health, such as out of pocket medical expenses or lost earnings, we estimate how the evolution of household assets is related to poor health. We construct a simple measure of health status based on the first principal component of HRS survey responses on self-reported health status, diagnoses, ADLs, IADL, and other indicators of underlying health. Our estimates suggest large and substantively important correlations between poor health and asset accumulation. We compare persons in each 1992 asset quintile who were in the top third of the 1992 distribution of latent health with those in the same 1992 asset quintile who were in the bottom third of the latent health distribution. By 2008, those in the top third of the health distribution had accumulated, on average, more than 50 percent more assets than those in the bottom third of the health distribution. This "asset cost of poor health" appears to be larger for persons with substantial 1992 asset balances than for those with lower balances.

WP 16418
Tanguy Brachet, Guy David, Reena Duseja
The Effect of Shift Structure on Performance: The Role of Fatigue for Paramedics

The effect of shift structure on worker performance and productivity is an issue of increasing interest to firms and regulatory bodies. Using approximately 742,000 emergency medical incidents attended by 2,400 paramedics in the state of Mississippi, we evaluate the extent to which paramedics' performance towards the end of their shift is impacted by its length. We find evidence that their performance deteriorates towards the end of long shifts, and argue that fatigue is the mediating factor. These findings have implications for workforce organization, calling attention to regulation designed to limit extended work hours.

This paper is the first to use the method of instrumental variables (IV) to estimate the impact of obesity on medical costs, in order to address the endogeneity of weight and to reduce the bias from reporting error in weight. Models are estimated using data from the Medical Expenditure Panel Survey for 2000-2005. The IV model, which exploits genetic variation in weight as a natural experiment, yields estimates of the impact of obesity on medical costs that are considerably higher than the correlations reported in the previous literature. For example, obesity is associated with $676 higher annual medical care costs, but the IV results indicate that obesity raises annual medical costs by $2,826 (in 2005 dollars). The estimated annual cost of treating obesity in the U.S. adult non-institutionalized population is $168.4 billion or 16.5% of national spending on medical care. These results imply that the previous literature has underestimated the medical costs of obesity, resulting in underestimates of the cost effectiveness of anti-obesity interventions and the economic rationale for government intervention to reduce obesity-related externalities.